Assighob to plymouth gypsum



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LOUIS E. ARIFWTMQITG, 0F FORT DODGE, IOWA, ASFTGNUR TU PLYMOUTH GYPSUM Ct'thtflfhtt, UJE FORT DODGE, TUWA, it. GURFUTTUN UTE TUWA. I

rtnsrna nonnn application nled July at,

To all whom it may concern:

Be it known that T, LOUIS; E. Amus'rnoNc, a citizen of the United States, and a resident of Fort Dodge, in the county'of Webster and State of lowa, have invented certain new and useful Improvements in Plaster Board, of which the following is a specification.

This invention relates to improvements in plaster board, and more particularly to that class of plaster board provided with a covered or sealed edge, whereby a'more finished product is obtaine 1 v The object of the invention is to'provide a new and useful construction for plaster board embodying a novel treatment of the edges whereby a more uniform and perfect sealing is attained, and smoother and stronger edges are produced.-

The construction and method of manufacture are clearly set forth in the following description, reference being had to the accompanying drawings, wherein,

Figure 1 is a perspective view of a fragment of plaster board with portions of the covering sheets folded back in order to more clearly reveal the construction,

Figure 2 is an enlarged cross-sectional view of the board as taken on line 2-2 of Figure 1, and

Figure 3 is a view of a fragment of the edge forming strip, showing the arrangement of the perforations.

Plaster board is a well lmown building material consisting of a relatively thin layer of plaster or stucco interposed between layers or sheets of tough paper. It is manufactured by a process whereby the wet plasall ter is fed between the sheets and rolled to the desired uniform thickness and cut into lengths of convenient size for handling, and. finally dried. The sealing or binding of the edges forms a part of the manufacturing process, whereby the side or longitudinal edges of the board are covered with pa er, thus entirely enveloping the plaster wit in its covering The plaster board herein illustrated is typical of the product in its general formatlon, consisting of the layer or body of stucco 1 interposed between the covering sheets 2-2 of paper, or other fibrous material, a tough grade of paper,however, being the common material used for this purpose. The cover sheets 2-2 (whichneed not be identiieaa. semi in. waste.

lied as the top or bottom sheet, inauch as the board is alike on bothsides) are of the same width as the finished board, their edges I terminating flush with the edges of the bodyv 1. Extending along the edges of the body it Throughout the marginal portions 5-5 are equidistantly spaced holesor perforations 6 of relatively largediameter, although the size, number and arrangement forations is not material. Where comparatlvely large perforations are used, however, they are preferably arranged in staggered relation on opposite sides of the central portion t, in order that they will not register with each other when the strip is incor porated into the board. The reason for this will be presently pointed out.

In the finished board, this-strip 3 extends along the edge of the board, the central portion at forming the edge face, and the margmal portions 5-5 being overlapped by the marginal portions of the cover sheets 2-2.

heets 2-2, and strip 3, by utilizing the adof these perhesive properties of the stucco. Thus in the I passage of the board through the pressing rolls of the machine, the wet stuccopasses through the perforations,adhering to the exposed under surface of the cover sheets, thereby forming a bond securely sealing the covering material along the edges of the board.

The advantages of a construction such as herein disclosed are numerous. The strip 3- completely encloses the margin of the body 1, thus providing a neat, regular and uniform edge. It further makes a clean edge; that is, an edge that is not impaired by quantities of plaster which would otherwise be squeezed out between the edges Hill Heb. 2U, 1923. 5 L445 A. G. ATWELL AUTOMATIC STOP FOR SOUND REPRODUCING MACHINES Filed Feb. 20, 192 

